Axis based compression for remote rendering

ABSTRACT

Disclosed herein are related to a system and a method of remotely rendering an image. In one approach, a console device generates an image according to a gaze direction of a user of a head mounted display (HMD). In one aspect, the image includes a first area and a second area disposed along an axis, where the second area is located farther away from a foveated area of the image than the first area. In one aspect, the foveated area corresponds to the gaze direction of the user of the HMD. In one aspect, the console device compresses the image according to the axis, where the second area is compressed at a higher level than the first area. In one aspect, the compressed image is transmitted to the HMD. The HMD may decompress the compressed image according to the axis, and render the decompressed image.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority under 35 U.S.C. § 120 asa continuation of U.S. Non-Provisional patent application Ser. No.16/579,017, filed on Sep. 23, 2019, the content of which is incorporatedherein by reference in its entirety.

FIELD OF DISCLOSURE

The present disclosure is generally related to processing an image of avirtual space, including but not limited to performing compression,decompression, or a combination of compression and decompression basedon axes to render an image of a virtual space.

BACKGROUND

Artificial reality such as a virtual reality (VR), an augmented reality(AR), or a mixed reality (MR) provides immersive experience to a user.In one example, a user wearing a head mounted display (HMD) can turn theuser's head, and an image of a virtual object corresponding to alocation of the HMD and a gaze direction of the user can be displayed onthe HMD to allow the user to feel as if the user is moving within aspace of an artificial reality (e.g., a VR space, an AR space, or a MRspace).

In one implementation, an image of a virtual object is generated by aconsole communicatively coupled to the HMD. In one example, the HMDincludes various sensors that detect a location of the HMD and a gazedirection of the user wearing the HMD, and transmits the detectedlocation and gaze direction to the console device through a wiredconnection or a wireless connection. The console device can determine auser's view of the space of the artificial reality according to thedetected location and gaze direction, and generate an image of the spaceof the artificial reality corresponding to the user's view. The consoledevice can transmit the generated image to the HMD, by which the imageof the space of the artificial reality corresponding to the user's viewcan be presented to the user. In one aspect, the process of detectingthe location of the HMD and the gaze direction of the user wearing theHMD, and rendering the image to the user should be performed within aframe time (e.g., less than 11 ms).

Any latency between a movement of the user wearing the HMD and an imagedisplayed corresponding to the user movement can cause judder, which mayresult in motion sickness and can degrade the user experience.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not intended to be drawn to scale. Likereference numbers and designations in the various drawings indicate likeelements. For purposes of clarity, not every component can be labeled inevery drawing.

FIG. 1 is a diagram of a system environment including an artificialreality system, according to an example implementation of the presentdisclosure.

FIG. 2 is a diagram of a head mounted display, according to an exampleimplementation of the present disclosure.

FIG. 3 is a diagram of a content provider, according to an exampleimplementation of the present disclosure.

FIG. 4 is a diagram of an image renderer, according to an exampleimplementation of the present disclosure.

FIG. 5A shows example images of a virtual reality before an axis basedcompression, according to an example implementation of the presentdisclosure.

FIG. 5B shows example images of virtual reality after the axis basedcompression, according to an example implementation of the presentdisclosure.

FIG. 6 is a flow chart illustrating a process of performing axis basedcompression, according to an example implementation of the presentdisclosure.

FIG. 7 is a flow chart illustrating a process of rendering an imagebased on axis based decompression, according to an exampleimplementation of the present disclosure.

FIG. 8 is a block diagram of a computing environment according to anexample implementation of the present disclosure.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate certain embodiments indetail, it should be understood that the present disclosure is notlimited to the details or methodology set forth in the description orillustrated in the figures. It should also be understood that theterminology used herein is for the purpose of description only andshould not be regarded as limiting.

Disclosed herein are related to systems and methods for remotelyrendering an image of a virtual object in an artificial reality space(e.g., an AR space, a VR space, or a MR space) through use of axis basedcompression/decompression. In one approach, a console device generatesan image according to a gaze direction of a user of a head mounteddisplay (HMD). The image (e.g., image pixels) may be divided orpartitioned into multiple areas or blocks according to axes (e.g.,geometric lines at least some of which may be straight or non-straight),that may be compressed or distorted individually, in groups, orcollectively. In one aspect, the image includes a first area and asecond area disposed along an axis, where the second area is locatedfarther away from a foveated area of the image than the first area. Insome embodiments, an edge or boundary of the first area or of the secondarea may lie along the axis. In some embodiments, the axes are imaginaryor virtual reference lines, and may not be visible to a user of the HMD.The axes may be straight lines or curved lines, or a combinationthereof, and may be geometrically or mathematically defined ordescribed. In one aspect, the foveated area corresponds to the gazedirection, area and/or point of the user of the HMD, and can representone portion or point of a field of view (FOV) of the user in theartificial reality space. In one aspect, the console device compressesthe image according to the axis, where the second area is compressed ata higher level than the first area. In one aspect, the console devicetransmits the compressed image to the HMD. The HMD may decompress thecompressed image according to the axis, and render the decompressedimage. In one example, the console device may generate a high qualityimage (e.g., 1920 by 1080 pixels), and compress edges or corners of theimage (e.g., corresponding to peripheral portions of the user's FOV,which are less important to the user) at a higher level than a center ora foveated area of the image. Hence, communication bandwidth between theconsole device and the HMD can be reduced due to the compression, whilepreserving fidelity of a center or a foveated area of the image.

FIG. 1 is a block diagram of an example artificial reality systemenvironment 100 in which a console 110 operates. In some embodiments,the artificial reality system environment 100 includes a HMD 150 worn bya user, and a console 110 providing content of artificial reality to theHMD 150. In one aspect, the HMD 150 may detect its location and a gazedirection of the user wearing the HMD 150, and provide the detectedlocation and the gaze direction to the console 110. The console 110 maydetermine a view within the space of the artificial realitycorresponding to the detected location and the gaze direction, andgenerate an image depicting the determined view. The console 110 mayprovide the image to HMD 150 for rendering. In some embodiments, theartificial reality system environment 100 includes more, fewer, ordifferent components than shown in FIG. 1. In some embodiments,functionality of one or more components of the artificial reality systemenvironment 100 can be distributed among the components in a differentmanner than is described here. For example, some of the functionality ofthe console 110 may be performed by the HMD 150. For example, some ofthe functionality of the HMD 150 may be performed by the console 110. Insome embodiments, the console 110 is integrated as part of the HMD 150.

In some embodiments, the HMD 150 is an electronic component that can beworn by a user and can present or provide an artificial realityexperience to the user. The HMD 150 may render one or more images,video, audio, or some combination thereof to provide the artificialreality experience to the user. In some embodiments, audio is presentedvia an external device (e.g., speakers and/or headphones) that receivesaudio information from the HMD 150, the console 110, or both, andpresents audio based on the audio information. In some embodiments, theHMD 150 includes sensors 155, eye trackers 160, a communicationinterface 165, an image renderer 170, an electronic display 175, a lens180, and a compensator 185. These components may operate together todetect a location of the HMD 150 and a gaze direction of the userwearing the HMD 150, and render an image of a view within the artificialreality corresponding to the detected location of the HMD 150 and thegaze direction of the user. In other embodiments, the HMD 150 includesmore, fewer, or different components than shown in FIG. 1.

In some embodiments, the sensors 155 include electronic components or acombination of electronic components and software components that detecta location and an orientation of the HMD 150. Examples of sensors 155can include: one or more imaging sensors, one or more accelerometers,one or more gyroscopes, one or more magnetometers, or another suitabletype of sensor that detects motion and/or location. For example, one ormore accelerometers can measure translational movement (e.g.,forward/back, up/down, left/right) and one or more gyroscopes canmeasure rotational movement (e.g., pitch, yaw, roll). In someembodiments, the sensors 155 detect the translational movement and therotational movement, and determine an orientation and location of theHMD 150. In one aspect, the sensors 155 can detect the translationalmovement and the rotational movement with respect to a previousorientation and location of the HMD 150, and determine a new orientationand/or location of the HMD 150 by accumulating or integrating thedetected translational movement and/or the rotational movement. Assumingfor an example that the HMD 150 is oriented in a direction 25 degreesfrom a reference direction, in response to detecting that the HMD 150has rotated 20 degrees, the sensors 155 may determine that the HMD 150now faces or is oriented in a direction 45 degrees from the referencedirection. Assuming for another example that the HMD 150 was located twofeet away from a reference point in a first direction, in response todetecting that the HMD 150 has moved three feet in a second direction,the sensors 155 may determine that the HMD 150 is now located at avector multiplication of the two feet in the first direction and thethree feet in the second direction.

In some embodiments, the eye trackers 160 include electronic componentsor a combination of electronic components and software components thatdetermine a gaze direction of the user of the HMD 150. In someembodiments, the eye trackers 160 include two eye trackers, where eacheye tracker 160 captures an image of a corresponding eye and determinesa gaze direction of the eye. In one example, the eye tracker 160determines an angular rotation of the eye, a translation of the eye, achange in the torsion of the eye, and/or a change in shape of the eye,according to the captured image of the eye, and determines the relativegaze direction with respect to the HMD 150, according to the determinedangular rotation, translation and the change in the torsion of the eye.In one approach, the eye tracker 160 may shine or project apredetermined reference or structured pattern on a portion of the eye,and capture an image of the eye to analyze the pattern projected on theportion of the eye to determine a relative gaze direction of the eyewith respect to the HMD 150. In some embodiments, the eye trackers 160incorporate the orientation of the HMD 150 and the relative gazedirection with respect to the HMD 150 to determine a gate direction ofthe user. Assuming for an example that the HMD 150 is oriented at adirection 30 degrees from a reference direction, and the relative gazedirection of the HMD 150 is −10 degrees (or 350 degrees) with respect tothe HMD 150, the eye trackers 160 may determine that the gaze directionof the user is 20 degrees from the reference direction. In someembodiments, a user of the HMD 150 can configure the HMD 150 (e.g., viauser settings) to enable or disable the eye trackers 160. In someembodiments, a user of the HMD 150 is prompted to enable or disable theeye trackers 160.

In some embodiments, the communication interface 165 includes anelectronic component or a combination of an electronic component and asoftware component that communicates with the console 110. Thecommunication interface 165 may communicate with a communicationinterface 115 of the console 110 through a communication link. Thecommunication link may be a wireless link, a wired link, or both.Examples of the wireless link can include a cellular communication link,a near field communication link, Wi-Fi, Bluetooth, or any communicationwireless communication link. Examples of the wired link can include aUSB, Ethernet, Firewire, HDMI, or any wired communication link. In theembodiments, in which the console 110 and the head mounted display 175are implemented on a single system, the communication interface 165 maycommunicate with the console 110 through a bus connection or aconductive trace. Through the communication link, the communicationinterface 165 may transmit to the console 110 data indicating thedetermined location of the HMD 150 and the determined gaze direction ofthe user. Moreover, through the communication link, the communicationinterface 165 may receive from the console 110 data indicating orcorresponding to an image to be rendered.

In some embodiments, the image renderer 170 includes an electroniccomponent or a combination of an electronic component and a softwarecomponent that generates one or more images for display, for example,according to a change in view of the space of the artificial reality. Insome embodiments, the image renderer 170 is implemented as a processor(or a graphical processing unit (GPU)) that executes instructions toperform various functions described herein. The image renderer 170 mayreceive, through the communication interface 165, data describing animage to be rendered, and render the image through the electronicdisplay 175. In some embodiments, the data from the console 110 may becompressed or encoded, and the image renderer 170 may decompress ordecode the data to generate and render the image. In one aspect, theimage renderer 170 receives the compressed image from the console 110,and decompresses the compressed image, such that a communicationbandwidth between the console 110 and the HMD 150 can be reduced. In oneaspect, the image renderer 170 performs decompression according to axesof the compressed image indicating how to perform decompression, asdescribed below with respect to FIGS. 4 and 7. In one aspect, theprocess of detecting, by the HMD 150, the location of the HMD 150 andthe gaze direction of the user wearing the HMD 150, and generating andtransmitting, by the console 110, a high resolution image (e.g., 1920 by1080 pixels, or 2048 by 2048 pixels) corresponding to the detectedlocation and the gaze direction to the HMD 150 may be computationallyexhaustive and may not be performed within a frame time (e.g., less than11 ms or 8 ms). In one aspect, the image renderer 170 generates one ormore images through a shading process and a reprojection process when animage from the console 110 is not received within the frame time. Forexample, the shading process and the reprojection process may beperformed adaptively, according to a change in view of the space of theartificial reality.

In some embodiments, the electronic display 175 is an electroniccomponent that displays an image. The electronic display 175 may, forexample, be a liquid crystal display or an organic light emitting diodedisplay. The electronic display 175 may be a transparent display thatallows the user to see through. In some embodiments, when the HMD 150 isworn by a user, the electronic display 175 is located proximate (e.g.,less than 3 inches) to the user's eyes. In one aspect, the electronicdisplay 175 emits or projects light towards the user's eyes according toimage generated by the image renderer 170.

In some embodiments, the lens 180 is a mechanical component that altersreceived light from the electronic display 175. The lens 180 may magnifythe light from the electronic display 175, and correct for optical errorassociated with the light. The lens 180 may be a Fresnel lens, a convexlens, a concave lens, a filter, or any suitable optical component thatalters the light from the electronic display 175. Through the lens 180,light from the electronic display 175 can reach the pupils, such thatthe user can see the image displayed by the electronic display 175,despite the close proximity of the electronic display 175 to the eyes.

In some embodiments, the compensator 185 includes an electroniccomponent or a combination of an electronic component and a softwarecomponent that performs compensation to compensate for any distortionsor aberrations. In one aspect, the lens 180 introduces opticalaberrations such as a chromatic aberration, a pin-cushion distortion,barrel distortion, etc. The compensator 185 may determine a compensation(e.g., predistortion) to apply to the image to be rendered from theimage renderer 170 to compensate for the distortions caused by the lens180, and apply the determined compensation to the image from the imagerenderer 170. The compensator 185 may provide the predistorted image tothe electronic display 175.

In some embodiments, the console 110 is an electronic component or acombination of an electronic component and a software component thatprovides content to be rendered to the HMD 150. In one aspect, theconsole 110 includes a communication interface 115 and a contentprovider 130. These components may operate together to determine a view(e.g., a FOV of the user) of the artificial reality corresponding to thelocation of the HMD 150 and the gaze direction of the user of the HMD150, and can generate an image of the artificial reality correspondingto the determined view. In other embodiments, the console 110 includesmore, fewer, or different components than shown in FIG. 1. In someembodiments, the console 110 is integrated as part of the HMD 150.

In some embodiments, the communication interface 115 is an electroniccomponent or a combination of an electronic component and a softwarecomponent that communicates with the HMD 150. The communicationinterface 115 may be a counterpart component to the communicationinterface 165 to communicate with a communication interface 115 of theconsole 110 through a communication link (e.g., USB cable). Through thecommunication link, the communication interface 115 may receive from theHMD 150 data indicating the determined location of the HMD 150 and thedetermined gaze direction of the user. Moreover, through thecommunication link, the communication interface 115 may transmit to theHMD 150 data describing an image to be rendered.

The content provider 130 is a component that generates content to berendered according to the location of the HMD 150 and the gaze directionof the user of the HMD 150. In one aspect, the content provider 130determines a view of the artificial reality according to the location ofthe HMD 150 and the gaze direction of the user of the HMD 150. Forexample, the content provider 130 maps the location of the HMD 150 in aphysical space to a location within a virtual space, and determines aview of the virtual space along the gaze direction from the mappedlocation in the virtual space. The content provider 130 may generateimage data describing an image of the determined view of the virtualspace, and transmit the image data to the HMD 150 through thecommunication interface 115. In some embodiments, the content provider130 generates metadata including motion vector information, depthinformation, edge information, object information, etc., associated withthe image, and transmits the metadata with the image data to the HMD 150through the communication interface 115. The content provider 130 maycompress and/or encode the data describing the image, and can transmitthe compressed and/or encoded data to the HMD 150. In one aspect, thecontent provider 130 performs compression according to axes of theimage, as described below with respect to FIGS. 3, 5A, 5B, and 6 forexample. In some embodiments, the content provider 130 generates andprovides the image to the HMD 150 periodically (e.g., every one second).

FIG. 2 is a diagram of a HMD 150, in accordance with an exampleembodiment. In some embodiments, the HMD 150 includes a front rigid body205 and a band 210. The front rigid body 205 includes the electronicdisplay 175 (not shown in FIG. 2), the lens 180 (not shown in FIG. 2),the sensors 155, the eye trackers 160A, 160B, and the image renderer170. In the embodiment shown by FIG. 2, the sensors 155 are locatedwithin the front rigid body 205, and may not visible to the user. Inother embodiments, the HMD 150 has a different configuration than shownin FIG. 2. For example, the image renderer 170, the eye trackers 160A,160B, and/or the sensors 155 may be in different locations than shown inFIG. 2.

FIG. 3 is a diagram of the content provider 130, according to an exampleimplementation of the present disclosure. In some embodiments, thecontent provider 130 includes an artificial space image generator 310, abase axes generator 315, a compression axes generator 320, and an imagecompressor 330. These components may generate an image of a view of anartificial reality, and compresses the image for transmission to the HMD150 according to two or more axes. In some embodiments, the contentprovider 130 includes more, fewer, or different components than shown inFIG. 3. In some embodiments, functionalities of some components of thecontent provider 130 can be performed by the HMD 150.

In some embodiments, the artificial space image generator 310 includes acomponent that detects, estimates, or determines a view of theartificial reality corresponding to the location and/or orientation ofthe HMD 150, and/or the gaze direction of the user of the HMD 150, andgenerates an image of the artificial reality corresponding to thedetermined view. In one approach, the artificial space image generator310 receives signals or data indicating the location of the HMD 150 andthe gaze direction of the user of the HMD 150 from the HMD 150. Theartificial space image generator 310 may map the location of the HMD 150in a physical space to a location within the artificial space, and candetermine a view of the artificial space along the gaze direction fromthe mapped location in the artificial space. In one approach, theartificial space image generator 310 may track a change in the locationof the HMD 150 and the gaze direction of the user of the HMD 150, andupdate the previous view of the space of the artificial realityaccording to the tracked change to determine the current view of theartificial space. For example, if a user turns his head 45 degrees, thena view of the artificial space rotated 45 degrees from the previous viewcan be determined. For another example, if a user moves a step forward,then a view of the artificial space from a virtual location shifted fromthe previous location by a distance corresponding to the step can bedetermined. The artificial space image generator 310 may generate animage of the determined view of the artificial space.

In some embodiments, the base axes generator 315 includes a componentthat generates base axes for the image. In one aspect, the base axes canbe straight or curved axes or lines, and can divide, segment orpartition the image (e.g. image pixels) into multiple areas or blocks(sometimes referred to as segments). In some embodiments, at least someof the base axes are curved axes or lines (e.g., non-straight lines).The base axes can segment an image into segments, on which distortion orcompression (e.g., radial barrel distortion, localized distortion,distributed distortion, symmetrical distortion, non-symmetricaldistortion, irregular distortion, grid-based distortion) can be applieduniformly or non-uniformly within each segment, according to the axes(e.g., according to how the base axes and/or compression axes define,segment, divide and/or arrange the image into segments). In someembodiments, the base axes include horizontal base axes and verticalbase axes that form a mesh. In one aspect, each horizontal base axis isseparated from its adjacent horizontal base axis by a unit distance, andeach vertical base axis is separated from its adjacent vertical baseaxis by a unit distance. In some embodiments, the base axes includediagonal base axes traversing the horizontal base axes and the verticalbase axes at a slanted angle. In some embodiments, the diagonal baseaxis, a horizontal base axis and a vertical base axis intersect at acenter of a foveated area. According to the base axes, compression ordecompression can be performed.

In some embodiments, the compression axes generator 320 includes acomponent that generates compression information. In one aspect, thecompression information indicates, describes, identifies and/or definescompression axes (and/or corresponding areas or blocks of the image, orhow these blocks are segmented or defined) for compressing the image.The compression information can include or describe a relationshipbetween an image (or block) prior to compression, and the image (orblock) after compression. For example, the compression information candescribe a compression ratio, e.g., for each block or image area. Thecompression information can describe the manner and/or extent ofcompression (e.g., vertical and/or horizontal compression, compressionalgorithm or method, compression axes, base axes, compressionratio/level) of a block.

In some embodiments, the compression axes are generated in apredetermined manner, or adaptively generated according to the foveatedarea. In some embodiments, the compression axes generator 320 modifiesthe base axes according to the foveated area to generate or obtain thecompression axes. In one approach, the compression axes generator 320determines, for a portion of a base axis between two intersecting baseaxes, a distance to the center or the foveated area, and reduces alength of the portion of the axis according to the determined distance.For example, the compression axes generator 320 determines, for aportion of a horizontal base axis between two adjacent vertical axes, adistance to the center or the foveated area, and adjusts or reduces(e.g., compresses) a length of the portion of the axis according to thedistance to obtain a corresponding horizontal compression axis. Forexample, a length of a first portion of the base axis farther away fromthe center or the foveated area than a second portion of the base axismay be reduced by a larger amount than the second portion of the baseaxis. In one approach, the compression axes generator 320 determines,for different portions of a base axis, distances to the center or thefoveated area, and adjusts lengths of different portions of the baseaxis according to the relative distances to the center or the foveatedarea to obtain compression axes. For example, a length of a portion ofthe base axis closest to the center or the foveated area may not bereduced, whereas a length of another portion of the base axis away fromthe center or the foveated area may be reduced according to a ratiobetween i) a distance from the portion of the base axis to the center orthe foveated area and ii) a distance from the another portion of thebase axis to the center or the foveated area.

In some embodiments, the compression axes generator 320 determines, foreach base axis, a reference point and reduces or adjusts lengths ofdifferent portions of the base axis according to the reference point. Inone aspect, a reference point of an axis is a point on the axis, throughwhich an orthogonal line (or an intersecting axis) orthogonal to theaxis from a center of the foveated area traverses. In one example, thecompression axes generator 320 determines, for each portion of the axisbetween two corresponding intersecting axes, a distance to the referencepoint, and determines an amount to reduce the length of the portionaccording to the distance. The compression axes generator 320 maycompare, for each distance, one or more predetermined thresholds, anddetermine an amount of length to reduce according to the comparison. Forexample, the compression axes generator 320 may determine that a firstportion of a horizontal axis between two intersecting vertical axes iswithin a first predetermined threshold (e.g., 50 pixels in length), anddetermine not to reduce a length of the first portion. For anotherexample, the compression axes generator 320 may determine that a secondportion of the horizontal axis is between the first predeterminedthreshold and a second predetermined threshold (e.g., 100 pixels), andmay determine to reduce a length of the second portion by a secondamount (e.g., 10%). For another example, the compression axes generator320 may determine that a third portion of the horizontal axis is betweenthe second predetermined threshold and a third predetermined threshold(e.g., 150 pixels), and determine to reduce a length of the thirdportion by a third amount (e.g., 20%).

In some embodiments, the image compressor 330 includes a component thatcompresses the image from the artificial space image generator 310according to the compression axes from the compression axes generator320. In one aspect, the image compressor 330 compresses a rectangularimage into another rectangular image, according to the compression axes.In one aspect, the image compressor 330 compresses an image (e.g.,rectangular or non-rectangular image) into another image (e.g.,rectangular or non-rectangular image), according to the compressionaxes. In some embodiments, at least some of the compression axes arecurved axes or lines (e.g., non-straight lines), and the compressionaxes generator 320 can perform distortion or compression (e.g., radialbarrel distortion, localized distortion, distributed distortion,symmetrical distortion, non-symmetrical distortion, irregulardistortion, grid-based distortion) according to the curved axes (e.g.,according to how the base axes and/or compression axes define, segment,divide and/or arrange the image into segments). For example, certainsegments of the image are distorted or compressed differently ascompared to some other segments of the image. In one approach, the imagecompressor 330 compresses a plurality of areas/blocks of the imagedefined by the base axes, to fit within corresponding spaces or areasdefined by the compression axes. In one example, the image compressor330 compares a length of a portion of a base axis with a length of acorresponding portion of a compression axis, and compresses an areaalong the base axis according to the comparison or a ratio between thelength of the portion of the base axis and the length of thecorresponding portion of the compression axis. In one aspect, the areais compressed along two intersecting axes in different amounts,according to distances along the intersecting axes from the area to thecenter or the foveated area. For example, the image compressor 330compresses an area by a first amount along the vertical axis andcompresses the area by a second amount along a horizontal axis. Theimage compressor 330 may transmit the compressed image and thecompression information to the HMD 150 through the communicationinterface 115. Additional examples of compressions are provided belowwith respect to FIGS. 5A, 5B, and 6, for example.

FIG. 4 is a diagram of an image renderer 170, according to an exampleimplementation of the present disclosure. In some embodiments, the imagerenderer 170 includes an image decompressor 405, an image partitioner410, a shading processor 420, a reprojection processor 430, and an imagerendering processor 440. These components may operate together toreceive a compressed image from the console 110 through thecommunication interface 165, and can decompress the compressed image forrendering. In one aspect, these components may operate together to applyadditional processes (e.g., a shading process, a reprojection process,compensation, predistortion, or any combination of them) for rendering.In other embodiments, the image renderer 170 includes more, fewer, ordifferent components than shown in FIG. 4. In some embodiments, theimage renderer 170 is designed and implemented to store or maintain aversion (e.g., details) of the world view corresponding to theartificial reality, even the unrendered parts of the world view, in someembodiments. The image renderer 170 can access, apply and/or render thedetails of the world view, e.g., as predictions about the 3D space ofthe artificial reality, as these come into view of a user due tomovement or interaction.

The image decompressor 405 may include a component that decompresses thecompressed image from the console 110 according to compression axes. Insome embodiments, the image decompressor 405 receives the compressedimage and the compression information from the console 110 through thecommunication interface 165, and decompresses the compressed imageaccording to the compression information. In one example, thecompression information indicates or includes compression axes. In oneaspect, the image decompressor 405 decompresses a rectangular image intoanother rectangular image, according to the compression axes. In oneaspect, the image decompressor 405 receives, generates, or stores baseaxes of the image, and compares the base axes with the compression axesto decompress the compressed image. In one approach, the imagedecompressor 405 decompresses a plurality of areas of the image definedby the compression axes to fit within corresponding spaces or areasdefined by base axes. In one example, the image decompressor 405compares a length of a portion of a base axis with a length of acorresponding portion of a compression axis, and decompresses an areaalong the compression axis according to the comparison or a ratiobetween the length of the portion of the compression axis and the lengthof the corresponding portion of the base axis. In one aspect, the areais decompressed along two intersecting axes in different amounts,according to distances along the intersecting axes from the area to thecenter or the foveated area. For example, the image decompressor 405decompresses an area by a first amount along the vertical axis anddecompresses the area by a second amount along a horizontal axis.

The image partitioner 410 may include a component that determinesdifferent portions of an image to generate through a shading process anda reprojection, according to a change in a view of an artificialreality. In some embodiments, the image partitioner 410 determines oridentifies different portions of the decompressed image from the imagedecompressor 405 to generate through the shading process and thereprojection process periodically at a refresh time (e.g., every onesecond). The refresh time may be predetermined or may be set accordingto a user input. In one approach, the image partitioner 410 determinesthe change in the view of the artificial reality, according to metadataassociated with the image from the console 110. For example, themetadata can indicate or include depth information, motion vectorinformation, and edge information. In one approach, the imagepartitioner 410 determines a portion of an image corresponding to motionvectors having amplitudes exceeding a predetermined threshold, anddetermines to generate that portion of the image through a shadingprocess. In one approach, the image partitioner 410 determines a portionof the image with an amount of change in depth from its previous imageexceeding a predetermined threshold, and may in response determine togenerate that portion of the image through a shading process. In oneapproach, the image partitioner 410 determines a portion of the imagecorresponding to an edge of a virtual object, and may in responsedetermine to generate that portion of the image through a shadingprocess. The image partitioner 410 may aggregate or combine differentportions determined according to motion vectors, depth and edges into afirst portion of the image to generate through the shading process. Theimage partitioner 410 may determine to generate a remaining portion (ora second portion) of the image through a reprojection process. In oneaspect, a shading process is computationally exhaustive. In one example,the image partitioner 410 determines to generate 15-20% of the imagethrough a shading process, and determines to generate 80˜85% of theimage through a reprojection process to save computational resourcesand/or achieve bandwidth efficiency.

The shading processor 420 can correspond to a component that generatesthe first portion of the image through a shading process. In oneapproach, the shading processor 420 simulates light from a virtual lightsource projected on a virtual object and represents shading on one ormore surfaces of the virtual object according to the light. For example,the shading is represented with different brightness or darkness,according to light from the virtual light source incident on one or moresurfaces of the virtual object. In one approach, brightness or darknessis determined according to a normal vector of a surface of a virtualobject with respect to the virtual light source and a distance of thesurface of the virtual object from the light source to represent depthin a three dimensional space of the virtual object.

In some embodiments, the shading processor 420 adaptively adjusts aresolution of shadings performed. In one aspect, the shading processor420 performs different levels of resolutions of shadings according todepth information, motion vector information, and edge information. Inone aspect, the shading processor 420 determines, within the firstportion of the image determined by the image partitioner 410, differentareas to perform shading and corresponding levels of resolutions ofshadings. For example, the shading processor 420 can perform the highestlevel of resolution of shading to generate a first area of the imagewith an edge of a virtual object within a foveated area to representdetails of shadings, and perform a lower level of resolution of shadinglower than the highest level to generate a second area that is adjacentto the first area away from the edge to represent lesser details of theshadings. In one approach, for different areas, different levels ofresolutions of shading can be performed by changing sizes of tiles indifferent areas of the image. For example, a higher level of resolutionof shading can be performed to generate an area of the image bydecreasing a size of a tile or decreasing a number of pixels per tile inthe area of the image such that finer details of shadings can berepresented for the area of the image. Conversely, a lower level ofresolution of shading can be performed to generate another area of theimage by increasing a size of a tile or a number of pixels per tile inthe another area of the image such that lesser details of shadings canbe represented for the another area of the image. By performingdifferent levels of resolutions of shadings to different areas,computational resources can be conserved by allocating lesscomputational resources to perform a shading process with lower levelsof resolutions to areas, in which the details of the shadings are lesssignificant.

The reprojection processor 430 may include or correspond to a componentthat generates a second portion of the image determined by the imagepartitioner through a reprojection process. In some embodiments, thereprojection processor 430 determines a filtering, a resolution, a rateor a frequency of reprojection to be applied, according to a change in aview of the artificial reality space. In one approach, the reprojectionprocessor 430 determines a rate of reprojection according to an amountof change in the view of the artificial reality space. The reprojectionprocessor 430 may increase the rate of reprojection, in response todetecting that the amount of change in the view of the artificialreality space is less than a predetermined threshold amount. Forexample, if the motion vector in the second portion of the image is lessthan a predetermined threshold, or if the change in the depth of avirtual object in the second portion of the image is less than apredetermined threshold, then the reprojection processor 430 mayincrease the rate of reprojection. For example, if the motion vector inthe second portion of the image exceeds a predetermined threshold or ifthe change in the depth of a virtual object in the second portion of theimage exceeds a predetermined threshold, then the reprojection processor430 may determine to apply a bicubic filtering for the reprojection. Forexample, the reprojection processor 430 can determine a first areawithin the second portion of the image farthest away from the firstportion of the image to generate through the shading process, anddetermine to perform the lowest level of resolution of reprojection togenerate the first area. For another example, the reprojection processor430 can determine a second area within the second portion of the imageadjacent to the first area closer to the first portion of the image togenerate through the shading process, and determine to perform a higherlevel of resolution of reprojection higher than the lowest level ofresolution to generate the second area. The reprojection processor 430may perform reprojection according to the determined filtering type,reprojection rate, and/or resolution.

The image rendering processor 440 can include or correspond to acomponent that generates an image to render according to the shadingprocess performed by the shading processor 420 and the reprojectionprocess performed by the reprojection processor 430. In one aspect, theimage rendering processor 440 combines the first portion of the imagegenerated by the shading processor 420 and the second portion of theimage generated by the reprojection processor 430 to generate the imageto be rendered. The image rendering processor 440 may provide thecombined image to the electronic display 175 for presentation. In someembodiments, the image generated by the image rendering processor 440may be processed or compensated by the compensator 185 to correct foroptical aberrations or distortions.

FIG. 5A shows example images 500A, 500B of a virtual reality before anaxis based compression is applied, according to an exampleimplementation of the present disclosure. The image 500A corresponds toa left eye view of an artificial reality, and the image 500B correspondsto a right eye view of the artificial reality, for example. In oneexample, the artificial space image generator 310 generates the images500A, 500B according to the location of the HMD 150 and the gazedirection of a user of the HMD 150. The base axes generator 315 maygenerate base axes including horizontal axes, vertical axes, anddiagonal axes. In one example, a horizontal axis H1, a vertical axis V1and two diagonal axes D1, D2 may intersect with each other at or near afoveated area for a left eye view of the artificial reality. Similarly,in one example, a horizontal axis H2, a vertical axis V2 and twodiagonal axes D3, D4 may intersect with each other at or near a foveatedarea for a right eye view of the artificial reality.

FIG. 5B shows example compressed images 550A, 550B of a virtual realityafter axis based compression is applied, according to an exampleimplementation of the present disclosure. In one example, thecompression axes generator 320 may generate compression axes based onthe base axes, and compresses the images 500A, 500B to generate thecompressed images 550A, 550B. In one example, a horizontal axis H1′, avertical axis V1′ and two diagonal axes D1′, D2′ may intersect with eachother at or near a foveated area for a left eye. Similarly, in oneexample, a horizontal axis H2′, a vertical axis V2′ and two diagonalaxes D3′, D4′ may intersect with each other at or near a foveated areafor a right eye. In one aspect, the compression axes are generated suchthat a distance between two adjacent compression axes are reduced oradjusted according to a distance from the foveated area. For example, adistance between two vertical axes near a left vertical side of thecompressed image 550A is smaller than a distance between two verticalaxes near the foveated area. For another example, a distance between twohorizontal axes near a top horizontal side of the compressed image 550Ais smaller than a distance between two horizontal axes near the foveatedarea. In one example, a first area B1 closer to the foveated area than asecond area B2 along the compression axis H1′ has a longer length alongthe compression axis H1′ than the second area B2, but the first area B1and the second area B2 have a same height. In one example, the secondarea B2 closer to the foveated area than a third area B3 along avertical compression axis has a longer height along the verticalcompression axis than the third area B3, but the second area B2 and thethird area B3 have a same length. Hence, a portion of the image near thefoveated area is preserved, while another portion of the image away fromthe foveated area is compressed. Accordingly, communication bandwidthfor transmitting and receiving the compressed image 550A, 550B can bereduced, without losing or sacrificing fidelity of information (e.g.,that may matter more to the user) near the foveated area.

In some embodiments, the compression axes generator 320 determines, foreach base axis, a reference point and reduces or adjusts lengths ofdifferent portions of the base axis according to the reference point. Inone aspect, a reference point of an axis is a point on the axis, throughwhich an orthogonal line (or an intersecting axis) orthogonal to theaxis from a center of the foveated area traverses. For example, ahorizontal base axis H3 has a reference point R1, and a horizontal baseaxis H4 has a reference point R2 that are intersected by the verticalbase axis V1 through the center of the foveated area. In one example,the compression axes generator 320 determines that a distance of a firstportion p1 of the horizontal base axis H4 to the reference point R2 iswithin a first predetermined threshold, and does not reduce a length ofthe portion p1 of the horizontal base axis H4 to generate acorresponding portion p1′ of the compression axis H4′. In one example,the compression axes generator 320 determines that a distance of asecond portion p2 of the horizontal base axis H4 to the reference pointR2 is between a second predetermined threshold and a third predeterminedthreshold, and reduces a length of the portion p2 of the horizontal baseaxis H4 by 50% to generate a corresponding portion p2′ of thecompression axis H4′. In one aspect, the horizontal compression axeshave the same length, and the vertical compression axes have the sameheight, such that the compressed images 550A, 550B generated accordingto the compression axes have a rectangular shape as shown in FIG. 5B.

FIG. 6 is a flow chart illustrating a process 600 of performing axisbased compression, according to an example implementation of the presentdisclosure. In some embodiments, the process 600 is performed by theconsole 110. In some embodiments, the process 600 is performed by otherentities. In some embodiments, the process 600 includes more, fewer, ordifferent steps than shown in FIG. 6.

In one approach, the console 110 retrieves 610 a first rectangularimage. In one approach, the console 110 receives signals indicating thelocation of the HMD 150 and the gaze direction of the user of the HMD150 from the HMD 150. The console 110 may map the location of the HMD150 in a physical space to a location within the artificial space, anddetermine a view of the artificial space along the gaze direction fromthe mapped location in the artificial space. In one approach, theconsole 110 may track a change in the location of the HMD 150 and thegaze direction of the user of the HMD 150, and update the previous viewof the space of the artificial reality according to the tracked changeto determine the current view of the artificial space. The console 110may generate an image of the determined view of the artificial space.

In one approach, the console 110 obtains 620 compression axes forcompressing the image. The compression axes may be generated in apredetermined manner, or adaptively generated according to the foveatedarea of the image. In one approach, the console 110 generates base axesdividing the image into multiple areas or blocks, then modifies oradjusts the base axes to generate or obtain the compression axes forcompressing the image. In some embodiments, the base axes includehorizontal base axes and vertical base axes that form a mesh. In oneaspect, each horizontal base axis is separated from its adjacenthorizontal base axis by a unit distance, and each vertical base axis isseparated from its adjacent vertical base axis by a unit distance. Insome embodiments, the base axes include diagonal base axes traversingthe horizontal base axes and the vertical base axes at a slanted angle.In some embodiments, the console 110 modifies the base axes according tothe foveated area to generate or obtain the compression axes. In oneapproach, the console 110 determines, for a portion of a base axisbetween two intersecting base axes, a distance to the center or thefoveated area, and adjusts or reduces a length of the portion of theaxis according to the determined distance. For example, the console 110determines, for a portion of a horizontal base axis between two adjacentvertical axes, a distance to the center or the foveated area, andadjusts or reduces a length of the portion of the axis according to thedistance to obtain a corresponding horizontal compression axis.

In one approach, the console 110 compresses 630 the first rectangularimage into a second rectangular image according to axes. In oneapproach, the console 110 compresses a plurality of areas or blocks ofthe image defined by the base axes to fit within corresponding spaces orareas defined by compression axes. In one example, the console 110compares a length of a portion of a base axis with a length of acorresponding portion of a compression axis, and compresses an areaalong the base axis according to the comparison or a ratio between thelength of the portion of the base axis and the length of thecorresponding portion of the compression axis. In one aspect, the areais compressed along two intersecting axes in different amounts,according to distances along the intersecting axes from the area to thecenter or the foveated area. For example, the console 110 compresses anarea by a first amount (e.g., 50%) along the vertical axis andcompresses the area by a second amount (e.g., 80%) along a horizontalaxis, according to a location of the area with respect to foveated area.

In one approach, the console 110 transmits 640 the second rectangularimage through a wireless or a wired connection (e.g., USB cable).Advantageously, by compressing the image through compression axes asdisclosed herein, communication bandwidth between the console 110 andthe HMD 150 can be reduced, while preserving fidelity of a center or afoveated area of the image.

FIG. 7 is a flow chart illustrating a process of rendering an imagebased on axis based decompression, according to an exampleimplementation of the present disclosure. In some embodiments, theprocess 700 is performed by the HMD 150. In some embodiments, theprocess 700 is performed by other entities. In some embodiments, theprocess 700 includes more, fewer, or different steps than shown in FIG.7.

In one approach, the HMD 150 retrieves 710 a compressed rectangularimage. In one approach, the HMD 150 obtains 720 compression information.In one example, the compression information indicates or includescompression axes (and/or provides an indication of blocks of thecompressed rectangular image to be decompressed, and/or information forperforming decompression of the blocks). In one approach, the HMD 150may receive the compressed image and the compression information fromthe console 110 together. In one approach, the compression informationmay be predetermined, and the HMD 150 may generate and store thecompression information prior to receiving the compressed image from theconsole 110.

In one approach, the HMD 150 decompresses 730 the compressed rectangularimage according to the compression information. In one aspect, the HMD150 decompresses a rectangular image into another rectangular image,according to the compression axes. In one approach, the HMD 150decompresses a plurality of areas or blocks of the image defined by thecompression axes to fit within corresponding spaces or areas defined bybase axes. In one example, the HMD 150 receives, generates, and/orstores base axes of the image, and compares the base axes with thecompression axes to decompress the compressed image. In one example, theHMD 150 compares a length of a portion of a base axis with a length of acorresponding portion of a compression axis, and decompresses an areaalong the compression axis according to the comparison or a ratiobetween the length of the portion of the compression axis and the lengthof the corresponding portion of the base axis. In one aspect, the areais decompressed along two intersecting axes in different amounts,according to distances along the intersecting axes from the area to thecenter or the foveated area. For example, the image decompressor 405decompresses an area by a first amount (e.g., 200%) along the verticalaxis and decompresses the area by a second amount (e.g., 125%) along ahorizontal axis, according to a location of the area with respect to thefoveated area.

In one approach, the HMD 150 renders 740 the image. In one example, theHMD 150 applies processes (e.g., shading process, reprojection process)to the decompressed image, and renders the process image. In oneexample, the HMD 150 may apply compensation or predistortion to correctfor optical aberrations or distortions due to the lens of the HMD 150,and renders the image according to the compensation.

Various operations described herein can be implemented on computersystems. FIG. 8 shows a block diagram of a representative computingsystem 814 usable to implement the present disclosure. In someembodiments, the console 110, the HMD 150 or both of FIG. 1 areimplemented by the computing system 814. Computing system 814 can beimplemented, for example, as a consumer device such as a smartphone,other mobile phone, tablet computer, wearable computing device (e.g.,smart watch, eyeglasses, head mounted display), desktop computer, laptopcomputer, or implemented with distributed computing devices. Thecomputing system 814 can be implemented to provide VR, AR, MRexperience. In some embodiments, the computing system 814 can includeconventional computer components such as processors 816, storage device818, network interface 820, user input device 822, and user outputdevice 824.

Network interface 820 can provide a connection to a wide area network(e.g., the Internet) to which WAN interface of a remote server system isalso connected. Network interface 820 can include a wired interface(e.g., Ethernet) and/or a wireless interface implementing various RFdata communication standards such as Wi-Fi, Bluetooth, or cellular datanetwork standards (e.g., 3G, 4G, 5G, 60 GHz, LTE, etc.).

User input device 822 can include any device (or devices) via which auser can provide signals to computing system 814; computing system 814can interpret the signals as indicative of particular user requests orinformation. User input device 822 can include any or all of a keyboard,touch pad, touch screen, mouse or other pointing device, scroll wheel,click wheel, dial, button, switch, keypad, microphone, sensors (e.g., amotion sensor, an eye tracking sensor, etc.), and so on.

User output device 824 can include any device via which computing system814 can provide information to a user. For example, user output device824 can include a display to display images generated by or delivered tocomputing system 814. The display can incorporate various imagegeneration technologies, e.g., a liquid crystal display (LCD),light-emitting diode (LED) including organic light-emitting diodes(OLED), projection system, cathode ray tube (CRT), or the like, togetherwith supporting electronics (e.g., digital-to-analog oranalog-to-digital converters, signal processors, or the like). A devicesuch as a touchscreen that function as both input and output device canbe used. Output devices 824 can be provided in addition to or instead ofa display. Examples include indicator lights, speakers, tactile“display” devices, printers, and so on.

Some implementations include electronic components, such asmicroprocessors, storage and memory that store computer programinstructions in a computer readable storage medium (e.g., non-transitorycomputer readable medium). Many of the features described in thisspecification can be implemented as processes that are specified as aset of program instructions encoded on a computer readable storagemedium. When these program instructions are executed by one or moreprocessors, they cause the processors to perform various operationindicated in the program instructions. Examples of program instructionsor computer code include machine code, such as is produced by acompiler, and files including higher-level code that are executed by acomputer, an electronic component, or a microprocessor using aninterpreter. Through suitable programming, processor 816 can providevarious functionality for computing system 814, including any of thefunctionality described herein as being performed by a server or client,or other functionality associated with message management services.

It will be appreciated that computing system 814 is illustrative andthat variations and modifications are possible. Computer systems used inconnection with the present disclosure can have other capabilities notspecifically described here. Further, while computing system 814 isdescribed with reference to particular blocks, it is to be understoodthat these blocks are defined for convenience of description and are notintended to imply a particular physical arrangement of component parts.For instance, different blocks can be located in the same facility, inthe same server rack, or on the same motherboard. Further, the blocksneed not correspond to physically distinct components. Blocks can beconfigured to perform various operations, e.g., by programming aprocessor or providing appropriate control circuitry, and various blocksmight or might not be reconfigurable depending on how the initialconfiguration is obtained. Implementations of the present disclosure canbe realized in a variety of apparatus including electronic devicesimplemented using any combination of circuitry and software.

Having now described some illustrative implementations, it is apparentthat the foregoing is illustrative and not limiting, having beenpresented by way of example. In particular, although many of theexamples presented herein involve specific combinations of method actsor system elements, those acts and those elements can be combined inother ways to accomplish the same objectives. Acts, elements andfeatures discussed in connection with one implementation are notintended to be excluded from a similar role in other implementations orimplementations.

The hardware and data processing components used to implement thevarious processes, operations, illustrative logics, logical blocks,modules and circuits described in connection with the embodimentsdisclosed herein may be implemented or performed with a general purposesingle- or multi-chip processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. A generalpurpose processor may be a microprocessor, or, any conventionalprocessor, controller, microcontroller, or state machine. A processoralso may be implemented as a combination of computing devices, such as acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration. In some embodiments, particularprocesses and methods may be performed by circuitry that is specific toa given function. The memory (e.g., memory, memory unit, storage device,etc.) may include one or more devices (e.g., RAM, ROM, Flash memory,hard disk storage, etc.) for storing data and/or computer code forcompleting or facilitating the various processes, layers and modulesdescribed in the present disclosure. The memory may be or includevolatile memory or non-volatile memory, and may include databasecomponents, object code components, script components, or any other typeof information structure for supporting the various activities andinformation structures described in the present disclosure. According toan exemplary embodiment, the memory is communicably connected to theprocessor via a processing circuit and includes computer code forexecuting (e.g., by the processing circuit and/or the processor) the oneor more processes described herein.

The present disclosure contemplates methods, systems and programproducts on any machine-readable media for accomplishing variousoperations. The embodiments of the present disclosure may be implementedusing existing computer processors, or by a special purpose computerprocessor for an appropriate system, incorporated for this or anotherpurpose, or by a hardwired system. Embodiments within the scope of thepresent disclosure include program products comprising machine-readablemedia for carrying or having machine-executable instructions or datastructures stored thereon. Such machine-readable media can be anyavailable media that can be accessed by a general purpose or specialpurpose computer or other machine with a processor. By way of example,such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, orother optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to carry or storedesired program code in the form of machine-executable instructions ordata structures and which can be accessed by a general purpose orspecial purpose computer or other machine with a processor. Combinationsof the above are also included within the scope of machine-readablemedia. Machine-executable instructions include, for example,instructions and data which cause a general purpose computer, specialpurpose computer, or special purpose processing machines to perform acertain function or group of functions.

The phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including” “comprising” “having” “containing” “involving”“characterized by” “characterized in that” and variations thereofherein, is meant to encompass the items listed thereafter, equivalentsthereof, and additional items, as well as alternate implementationsconsisting of the items listed thereafter exclusively. In oneimplementation, the systems and methods described herein consist of one,each combination of more than one, or all of the described elements,acts, or components.

Any references to implementations or elements or acts of the systems andmethods herein referred to in the singular can also embraceimplementations including a plurality of these elements, and anyreferences in plural to any implementation or element or act herein canalso embrace implementations including only a single element. Referencesin the singular or plural form are not intended to limit the presentlydisclosed systems or methods, their components, acts, or elements tosingle or plural configurations. References to any act or element beingbased on any information, act or element can include implementationswhere the act or element is based at least in part on any information,act, or element.

Any implementation disclosed herein can be combined with any otherimplementation or embodiment, and references to “an implementation,”“some implementations,” “one implementation” or the like are notnecessarily mutually exclusive and are intended to indicate that aparticular feature, structure, or characteristic described in connectionwith the implementation can be included in at least one implementationor embodiment. Such terms as used herein are not necessarily allreferring to the same implementation. Any implementation can be combinedwith any other implementation, inclusively or exclusively, in any mannerconsistent with the aspects and implementations disclosed herein.

Where technical features in the drawings, detailed description or anyclaim are followed by reference signs, the reference signs have beenincluded to increase the intelligibility of the drawings, detaileddescription, and claims. Accordingly, neither the reference signs northeir absence have any limiting effect on the scope of any claimelements.

Systems and methods described herein may be embodied in other specificforms without departing from the characteristics thereof. References to“approximately,” “about” “substantially” or other terms of degreeinclude variations of +/−10% from the given measurement, unit, or rangeunless explicitly indicated otherwise. Coupled elements can beelectrically, mechanically, or physically coupled with one anotherdirectly or with intervening elements. Scope of the systems and methodsdescribed herein is thus indicated by the appended claims, rather thanthe foregoing description, and changes that come within the meaning andrange of equivalency of the claims are embraced therein.

The term “coupled” and variations thereof includes the joining of twomembers directly or indirectly to one another. Such joining may bestationary (e.g., permanent or fixed) or moveable (e.g., removable orreleasable). Such joining may be achieved with the two members coupleddirectly with or to each other, with the two members coupled with eachother using a separate intervening member and any additionalintermediate members coupled with one another, or with the two memberscoupled with each other using an intervening member that is integrallyformed as a single unitary body with one of the two members. If“coupled” or variations thereof are modified by an additional term(e.g., directly coupled), the generic definition of “coupled” providedabove is modified by the plain language meaning of the additional term(e.g., “directly coupled” means the joining of two members without anyseparate intervening member), resulting in a narrower definition thanthe generic definition of “coupled” provided above. Such coupling may bemechanical, electrical, or fluidic.

References to “or” can be construed as inclusive so that any termsdescribed using “or” can indicate any of a single, more than one, andall of the described terms. A reference to “at least one of ‘A’ and ‘B’”can include only ‘A’, only ‘B’, as well as both ‘A’ and ‘B’. Suchreferences used in conjunction with “comprising” or other openterminology can include additional items.

Modifications of described elements and acts such as variations insizes, dimensions, structures, shapes and proportions of the variouselements, values of parameters, mounting arrangements, use of materials,colors, orientations can occur without materially departing from theteachings and advantages of the subject matter disclosed herein. Forexample, elements shown as integrally formed can be constructed ofmultiple parts or elements, the position of elements can be reversed orotherwise varied, and the nature or number of discrete elements orpositions can be altered or varied. Other substitutions, modifications,changes and omissions can also be made in the design, operatingconditions and arrangement of the disclosed elements and operationswithout departing from the scope of the present disclosure.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below”) are merely used to describe the orientation of variouselements in the FIGURES. The orientation of various elements may differaccording to other exemplary embodiments, and that such variations areintended to be encompassed by the present disclosure.

What is claimed is:
 1. A device comprising: at least one processorconfigured to: receive, from another device through a communicationlink, a compressed image, the compressed image including a first set ofareas allocated by a first set of non-uniformly spaced axes and a secondset of non-uniformly spaced axes intersecting the first set ofnon-uniformly spaced axes, the first set of areas including a first areaand a second area, along an axis of the first set of non-uniformlyspaced axes, the second area located farther away from a foveated areaof the compressed image than the first area, modify the compressed imageto obtain a modified image by decompressing the compressed imageaccording to compression information indicating the first set ofnon-uniformly spaced axes and the second set of non-uniformly spacedaxes, the modified image including a second set of areas allocated by athird set of uniformly spaced axes and a fourth set of uniformly spacedaxes intersecting the third set of uniformly spaced axes, the secondarea decompressed at a higher level than the first area, and render themodified image to a user of the device.
 2. The device of claim 1,wherein the at least one processor is configured to detect a gazedirection of the user, wherein the foveated area corresponds to the gazedirection of the user.
 3. The device of claim 1, wherein the axis isparallel to a horizontal side of the compressed image, or is parallel toa vertical side of the compressed image.
 4. The device of claim 1,wherein the second area has a smaller size than the first area, whereinthe decompressed second area and the decompressed first area have a samesize.
 5. The device of claim 1, wherein each of the third set ofuniformly spaced axes corresponds to a respective one of the first setof non-uniformly spaced axes, and wherein each of the fourth set ofuniformly spaced axes corresponds to a respective one of the second setof non-uniformly spaced axes.
 6. The device of claim 1, wherein the atleast one processor is configured to apply a predistortion to thedecompressed image to correct for a distortion due to a lens of thedevice.
 7. The device of claim 1, wherein the at least one processor isconfigured to receive the compression information with the compressedimage.
 8. The device of claim 1, wherein the at least one processor isconfigured to store the compression information prior to receiving thecompressed image.
 9. The device of claim 1, wherein the at least oneprocessor is configured to: compare a length of a portion of the axiswith a length of a corresponding portion of another axis, determine aratio between the length of the portion of the axis and the length ofthe corresponding portion of the another axis, and modify the compressedimage by decompressing the compressed image according to the determinedratio.
 10. A method comprising: receiving, by a device from anotherdevice through a communication link, a compressed image, the compressedimage including a first set of areas allocated by a first set ofnon-uniformly spaced axes and a second set of non-uniformly spaced axesintersecting the first set of non-uniformly spaced axes, the first setof areas including a first area and a second area, along an axis of thefirst set of non-uniformly spaced axes, the second area located fartheraway from a foveated area of the compressed image than the first area;modifying, by the device, the compressed image to obtain a modifiedimage by decompressing the compressed image according to compressioninformation indicating the first set of non-uniformly spaced axes andthe second set of non-uniformly spaced axes, the modified imageincluding a second set of areas allocated by a third set of uniformlyspaced axes and a fourth set of uniformly spaced axes intersecting thethird set of uniformly spaced axes, the second area decompressed at ahigher level than the first area; and rendering the modified image to auser of the device.
 11. The method of claim 10, comprising: detecting agaze direction of the user, wherein the foveated area corresponds to thegaze direction of the user.
 12. The method of claim 10, wherein the axisis parallel to a horizontal side of the compressed image, or is parallelto a vertical side of the compressed image.
 13. The method of claim 10,wherein the second area has a smaller size than the first area, whereinthe decompressed second area and the decompressed first area have a samesize.
 14. The method of claim 10, wherein each of the third set ofuniformly spaced axes corresponds to a respective one of the first setof non-uniformly spaced axes, and wherein each of the fourth set ofuniformly spaced axes corresponds to a respective one of the second setof non-uniformly spaced axes.
 15. The method of claim 10, comprising:applying a predistortion to the decompressed image to correct for adistortion due to a lens of the device.
 16. The method of claim 10,comprising: receiving the compression information with the compressedimage.
 17. The method of claim 10, comprising: storing the compressioninformation prior to receiving the compressed image.
 18. The method ofclaim 10, comprising: comparing a length of a portion of the axis with alength of a corresponding portion of another axis; determining a ratiobetween the length of the portion of the axis and the length of thecorresponding portion of the another axis; and modifying the compressedimage by decompressing the compressed image according to the determinedratio.
 19. A non-transitory computer readable medium storing programinstructions for causing at least one processor of a device to implementoperations of: receiving, from another device through a communicationlink, a compressed image, the compressed image including a first set ofareas allocated by a first set of non-uniformly spaced axes and a secondset of non-uniformly spaced axes intersecting the first set ofnon-uniformly spaced axes, the first set of areas including a first areaand a second area, along an axis of the first set of non-uniformlyspaced axes, the second area located farther away from a foveated areaof the compressed image than the first area, modifying the compressedimage to obtain a modified image by decompressing the compressed imageaccording to compression information indicating the first set ofnon-uniformly spaced axes and the second set of non-uniformly spacedaxes, the modified image including a second set of areas allocated by athird set of uniformly spaced axes and a fourth set of uniformly spacedaxes intersecting the third set of uniformly spaced axes, the secondarea decompressed at a higher level than the first area, and renderingthe modified image to a user of the device.
 20. The non-transitorycomputer readable medium of claim 19, wherein the second area has asmaller size than the first area, wherein the decompressed second areaand the decompressed first area have a same size.